Theophylline, aminophylline and dyphylline ae members of what group of drugs?
What are the 3 naturally-occurring methylxanthines?
Caffeine, theophylline and theobromine.
Name 3 synthetic methylxanthines.
1. dyphylline 2. proxyphilline 3) enprofylline
What is the brand name of the xanthine derivative oxtriphylline?
What is the brand name of aminophylline?
What is the brand name of dyphylline?
Clinical uses of theophylline include: (3)
management of asthma; COPD; apnea of prematurity
T/F Xanthines generally have sedative properties.
False. Generally have stimulant properties.
stimulation; seizures, cerebral vasoconstriction
cardiac muscle stimulation; peripheral and coronary vasodilation
relaxation of bronchial, uterine, and vascular
T/F The mode of action of xanthines is unclear.
True; may be related to antagonism of adenosine receptors.
Why is it necessary to titrate the dosage of thoeophylline to the individual?
The rate of metabolism varies by each person.
What is the therapeutic serum level of theophylline in COPD management?
What is the therapeutic serum level of theophylline in asthma management?
T/F Theophylline has a wide therapeutic margin because each individual metabolizes it differently.
False. Each individual metabolizes it differently, but the therapeutic margin is still narrow. Blood levels of theophylline are affected by many factors, which can either increase or decrease the amount of drug in the body.
Theophylline is considered in the treatment of asthma ONLY if what two other types of drugs fail to control symptoms?
β agonists and antiinflammartories
In COPD, what are two effects (non-bronchodilating) for which theophylline is valuable?
Ventilatory drive stimulation and enhanced respiratory muscle (diaphragm) function
Why do COPD guidelines suggest the use of inhaled β agonists and inticholinergics over theophylline?
B/c of the side effects of theophlline.
What is the definition of alkaloids?
Group of alkaline substances taken from plants, which react with acids to form salts, e.g. theophylline
Chemical group of drugs derived from xantihines.
Name the 3 naturally-occurring methylated xanthines.
Caffeine, theophylline and theobromine.
Define phosphodiesterase (PDE)
Group of enzymes that change intracellular signaling.
Nitrogenous compound found in many organs and in the blood and urine.
Why is theophylline NOT the first-line drug for asthma and COPD?
It has a relatively weak bronchodilating effect compared to β agonists.
Therapeutic action of theophylline action may be by : (2)
1) Stimulation of ventilatory drive 2) direct strengthening of the diaphragm.
What type of theophylline is indicated for maintenance (step 2) of mild persistant asthma in patients 5 yrs and up?
Sustained release theophylline.
In step 3, with patients 5 yrs and up, what drug combination may be used for maintenance treatment of asthma?
Sustained release theophylline with inhaled corticosteroid (ICS)
Compare effects of caffeine and theophylline on: 1) CNS stimulation 2) Cardiac stimulation 3) Smooth muscle relaxation 4) Skeletal muscle relaxatoin 5)Diuresis
CaffeineTheophylline 1) CNS stimulation: Caff +++ Theo ++ 2) Cardiac stim: Caff + Theo +++ 3) Smooth muscle relaxation Caff + Theo +++ 4) Skeletal muscle relaxation Caff +++ Theo ++ 5) Diuresis Caff + Theo +++
The standard with which salts of theophylline are compared is:
anhydrous theophylline. Anhydrous theophylline is 100% theophylline.
T/F Salts of theophylline, such as oxytriphylline are 100% theophylline by weight.
False. Oxytriphylline is only 64% pure theophylline.
T/F Dyphylline, a derivative of theophylline, is about 1/10th as potent as theophylline.
Name 3 proposed theories of activity to explain the mechanism of action of xanthines.
1) Inhibition of phosphodiesterase 2) Antagonism of adenosine 3) Catecholamine release
What is the effect of an increase in cAMP on bronchial smooth muscle?
Relaxation of bronchial smooth muscle.
T/F Theophylline is a selective inhibitor of cAMP specific phosphodiesterase (PDE), having a synergistic effect on bronchial smooth muscle.
False. Theophylline is a weak and noselective inhibitor of cAMP-specific PDE.
Adenosine stimulates A-1 and A-2 receptors. What is its effect on each of these?